Hill known as "the peerless orator" for his skill in delivering speech,[2] was the only non-Democratic member of the Georgia secession convention on January 16, 1861, where he spoke publicly against the dissolution of the Union, along with Alexander Stephens, a former opponent. Following Stephens' highly regarded argument based on a conservative reading of the Constitution, Hill struck a more pragmatic tone. His arguments related to the conservative belief that disunion would ultimately lead to the abolition of slavery and the downfall of Southern society. He quoted Henry Ward Beecher, a Northern abolitionist who enthusiastically supported the dissolution of the Union as a means to end slavery, and described the anti-slavery Republican Party as a "disunionist" party, in contrast to the "Union men and Southern men" participating in the convention. Acknowledging the need to respond to the threat of Lincoln's election, Hill argued that his fellow Georgians should continue to resist Lincoln democratically within the bounds of the Constitution. He compared this course to George Washington, "so cool, so brave, and so thoughtful." He argued that the Northern states would eventually follow the British course of rising abolitionist thought, followed by acceptance again of slavery due to economic necessity. But he allowed that the South should prepare for secession and war if it should become necessary.[3]

Unlike many Confederate politicians, Hill had a long and distinguished career as a "reconstructed" Southerner and U.S. politician. He ultimately became a Democrat after the Civil War ended. He spoke out passionately against Radical Reconstruction and in the summer of 1867 made a series of speeches in Atlanta, the most famous being the Davis House speech of July 16, 1867, denouncing the Reconstruction Acts of 1867. His courage and eloquence enhanced his regional fame and won him national recognition.

In 1875 he was elected to the U. S. House of Representatives, serving from May 5, 1875 - March 3, 1877. He quickly won a reputation as a spokesman for the South. He was later elected by the Georgia legislature to the U.S. Senate on January 26, 1877, as Reconstruction was ending. He served in the U.S. Senate from March 4, 1877, until his death on August 16, 1882. His obituary was featured on the front page of the Atlanta Constitution, on August 17, 1882.

^[1] Ferguson, Stuart, "The Zealotry of the Convert: Slavery's Firebrand Defender," book review of Eric H. Walther's William Lowndes Yancey and the Coming of the Civil War, in The Wall Street Journal, 8 July 2006; page P9; accessed on July 14, 2006